Ingrown nail (onychocryptosis)

Ingrown toenails are a common problem, especially on the big toes. They are often caused by the nails being cut incorrectly. If the skin has already become inflamed, the treatment depends on the severity of the discomfort. Proper nail care prevents inflammation.

At a glance

  • Ingrown nails are a common occurrence, especially on the big toes.
  • The nail grows into the skin which restricts it at the sides.
  • The affected area becomes inflamed, which can be painful.
  • In medical terms, an ingrown nail is known as unguis incarnatus or onychocryptosis.
  • Heavy perspiration, tight footwear and improper nail care can encourage ingrown toenails.

Note: The information in this article cannot and should not replace a medical consultation and must not be used for self-diagnosis or treatment.

Ingrown nail: doctor wearing a surgical glove touching a young person’s big toe with two fingers. There is an ingrown nail on the toe. The skin around the toenail is slightly red.

What is an ingrown toenail?

In medical terms, an ingrown nail is known as unguis incarnatus or onychocryptosis.

On the big toes in particular, the nail often grows into the skin which restricts it at the sides. This can cause localized inflammation and pain.

Heavy perspiration, tight footwear and cutting the nails incorrectly can make ingrown toenails more likely to develop.

Diagram showing anatomical structure of a finger: edge of nail at the top and below it the nail plate, lateral nail fold, cuticle and proximal nail fold. A second diagram shows the nail bed, nail root and bones of a finger in cross-section.

What are the symptoms of an ingrown toenail?

If the toenail grows into the skin, inflammation occurs. The affected area is supplied with more blood and redness, swelling and pain can occur.

Sometimes, new tissue (“proud flesh”) may form and grow over the nail. This is known in medical terms as granulation tissue as the surface of the new tissue looks like small granules (from the Latin “granulum”). The inflamed area can weep, bleed or release pus. The affected area can also smell unpleasant, especially if bacteria get into the wound.

What causes ingrown toenails?

Ingrown toenails are generally caused by one side of the nail pushing into the skin and continuing to grow. If this damages the skin and the soft tissue underneath, inflammation occurs.

Ingrown toenails are often caused by:

  • toenails being cut too short or rounded at the corners
  • shoes being too tight
  • sweaty feet
  • certain hereditary forms of nail growth, such as curved or tubular nails (“involuted toenails”)
  • obesity (adipositas)
  • diseases like diabetes mellitus and conditions that can cause water retention in the feet, such as cardiac, renal or chronic venous insufficiency
  • treatment with cancer drugs

How often do ingrown toenails occur?

20 of every 100 people who visit a doctor due to foot pain have an ingrown toenail.

20 von 100 Menschen, die wegen Fußbeschwerden zum Arzt gehen, haben einen eingewachsenen Zehennagel.

Adolescents and young adults are particularly affected. At this age, heightened perspiration increases the risk of an ingrown nail, for example as a result of sport or hormonal changes during puberty.

However, ingrown nails are also a common ailment among older people. These often find it harder to look after their feet and toenails as they are less supple. Furthermore, as people age, their toenails thicken, making them harder to cut. Typical old-age diseases such as diabetes can also promote ingrown toenails.

How does an ingrown toenail develop?

An ingrown nail is painful and therefore generally noticed at a very early stage. Those who react in time can often treat the inflammation themselves with just a few aids. The area will then heal without consequence.

However, if the patient has a weakened immune system and if bacteria have colonized the wound, the inflammation can spread. This can result in purulent inflammation around the entire nail or under the nail plate. In such cases, patients should consult their family doctor. This applies in particular if they are also experiencing a high temperature and fatigue, and if the inflammation continues to spread and develops into a “phlegmon” – a purulent inflammation of the soft tissue below the nail.

How can you prevent an ingrown toenail?

Correct foot care is especially important in preventing ingrown toenails. Particular care should be taken when cutting the nails – the corners of the nails should not be rounded and the nails should remain long enough for their corners to lie freely on the skin around their edges.

The toes should also have plenty of space in shoes. Open-toed or breathable shoes counteract heavy perspiration.

Ingrown nails can be prevented by correct foot care, which is particularly important, above all when cutting nails. Open or breathable shoes help to prevent excessive sweating.

How is an ingrown toenail diagnosed?

An ingrown toenail can be detected without any complex investigations. Doctors take a close look at the affected toe and ask about any discomfort and possible triggers.

If complications such as a phlegmon are indicated, additional investigation may be required – for example through a blood test.

How is an ingrown toenail treated?

The treatment of ingrown toenails depends on the severity of the discomfort they are causing.

In the case of mild inflammation with little pain, it can suffice to take a warm foot bath in soapy water and then treat the wound site with disinfectant (antiseptic) or anti-inflammatory tinctures, gels or ointments. The important things to remember are to thoroughly dry the foot after the bath, to avoid applying pressure to the affected nail and to not put shoes back on straight away.

Special dressings or nail braces can help the nail grow freely again. These can be provided by medical foot care (podology) practices.

If there is an increased risk of foot problems, for example due to diabetes, patients should consult a doctor. A visit to the doctor is generally required if the aforementioned treatments do not improve the condition or the ingrown nail releases pus and has become greatly inflamed. In such cases surgery may be needed. There are various procedures and techniques that patients should obtain detailed advice about.

For more detailed information about treating ingrown nails, for example about home remedies, visit

What effect do ingrown toenails have on everyday life?

The inflammation caused by an ingrown toenail can lead to pain when standing and walking. In such cases, it is important to reduce the pressure on the nail, for example by wearing open-toed shoes and wide socks. The foot should also be free at night and the bed cover should not directly touch the affected toe. This can be done by hanging the cover over the bed’s footboard to leave room for the toe.

Some people find regular foot and nail care difficult – for instance because they have joint problems and struggle to reach their feet.

Anyone who is unable to or doesn’t want to get help from a partner or family member can seek professional support instead.

  • If feet and toenails are healthy and there are no risk factors such as diabetes mellitus, cosmetic foot care practitioners can help. They will shorten the nails and remove calluses during a pedicure. Patients have to cover the costs themselves.
  • If health problems already exist, medical foot care from a podologist is recommended. The costs of podological treatment are sometimes covered by health insurance providers – for example if foot issues have been caused by diabetes mellitus.

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  • Heidelbaugh JJ, Lee H. Management of the ingrown toenail. Am Fam Physician 2009; 79(4): 303-308.
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  • Schumpelick V, Bleese N, Mommsen U (Eds.). Kurzlehrbuch Chirurgie. Stuttgart 2010.

In cooperation with the Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen – IQWiG).

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